Various biological materials are typically stored below freezing. For long-term storage, cells, peptides, or nucleic acids can be stored at −80° C., −20° C., or in liquid nitrogen at −195° C. Short-term storage can include temperatures at or greater than 0° C.
Many biological experiments are typically conducted at temperatures greater than these storage temperatures. For example, eukaryotic cells are often grown at 37° C., while prokaryotic cells often prefer different temperatures.
Traditionally, biological materials are aliquoted in vials and frozen for storage. To heat these vials, a person would usually take each vial and place it in a hot water bath. The person would carefully stir the vial in the bath to ensure uniform heating of the vials contents and to swirl the biological material within the vial. After some time, the person would remove the vial from the water bath and determine if the contents had sufficiently thawed. Once properly thawed, the biological material would be ready for use.
Several problems exist with traditional heating protocols. Firstly, the chance of contamination is high, as multiple vials are usually placed in the same water bath. To ensure sterility, the vial is typically wiped with an ethanol solution following removal from the water bath. However, the wipe may not be completely effective, and contaminants may remain on the vial or cap surface.
Secondly, the heating process may not be repeatable from vial to vial, as operators introduce human variability. Heating times, swirling duration, swirling speed, etc. may all vary significantly. Because some biological materials are sensitive to differing thermal gradients, shear forces, or agitation levels, experimental outcomes can be affected.
Thirdly, tracking vials using traditional water baths can be difficult. Labels can be removed by the warm water, and markings on the vials can be inadvertently removed by the ethanol wipe.
Finally, thawing may not include uniform heat dispersion. If a portion of material thaws and is not mixed correctly, refreezing may occur. Refreezing can cause re-crystallization and damage cells. An improved thawing device should be optimized to reduce non-uniform thawing and re-crystallization. Accordingly, there is a need for systems and methods to better thaw biological materials.